Transmission control



Jan. 6, 1953 L. B. EORMAN 2,624,206

Y TRANSMISSION CONTROL SYSTEM 2 SHEETS-SPEET l Filed July 24, 1951 wrap/vifs.'

n 6 2 d S m, T mw@ 4. m E im n, y mf n. T f I L. B. FORMAN TRANSMISSION CONTROL SYSTEM l Patented Jan. 6, 1953 UNITED STATES 2,624,206 TRANSMIS SION CONTRIGL 'SYSTEM Louis B. Forman,

Chrysler Corporation, `corporation of Delaware Detroit, Mich., assigner to Highland Park, Mich., a

Application July 24, 1951, vserial No. assess (ci. rea-472) 7 Claims.

mission co-ntrol systems wherein the disengagev ment of positively engageable drive control elements is facilitated by relieving the torque load on these elements as by momentary interruption of the engine ignition system. Examples of ytransmissions of this character are described in the Apatents to Carl A. Neracher et al. 2,455,943, granted December 14, 1948, and Augustin J. Syrovy et al. 2,490,604, granted December 6, 1949.

It has been customary, as shown by 'the aforesaid patentato provide a shiftable 'drive control element of toothed character arranged to interengage with a second toothed drive control element after passing through a toothed blocker. Engagement occurs upon synchronism obtaining between the drive control 'elements subsequent to engine deceleration by accelerator releasing movement, and the shiftable element is adapted to be unloaded, as described above, to facilitate its disengagement from its companion drive control element.

The drive control elements are generally Aso arranged in the transmission that upon relative engagement under governor control at or above a predetermined vehicle speed, there is provided a fast speed ratio drive through the transmission, usually a direct drive, and when relatively disengaged under governor control below va predetermined speed, or by kickdown means such as accelerator actuated switch means overruling the governor, there is provided another speed ratio drive which is usually a slower speed ratio drive than the rst mentioned one.

, Also customarily provided are prime mover or diiferential pressure servomotor means which may comprise a spring and a hydraulic or vacuum operated motor having a movable piston, for controlling shift of the shiftable drive control element through an associated shift rail or lever system. In the case of the hydraulic system, -as typified by the Syrovy et al.. patent aforesaid, .pressure fluid acting upon the piston will cause it to compress a disengaging spring and an engaging spring, and build up sufficient available force in the latter to move the shift rail and by it the shiftable'drive control element against its blocker and then into engagement withits companion drive control element when synchronization of the drive control elements subsequently occurs.

VIn the-case of the vacuum power system, as

typiied by the Neracher et al. patent, vacuum is utilized to cause the piston to compress a disengaging spring and through a rod extension of the piston, unload an engaging spring .previously tensioned by operation of the rod, Vthe latter spring in turn acting upon a lever to eiiect movement of the shiftable element against its blocker and into Vsubsequent engagement -with its companion drive control element when the drive control elements obtain synchronism.

Transmission Vsystems of the aforesadtypical character also usually include electromagnetically controlled valving for controlling venting (admission of atmospheric pressure) of the servomotor and operation of the piston such that when the motor is vented, the disengaging springac tuates the .piston to effect disengaging shift of the shiftable drive control element accompanied by ignition interruption, the latter occurring vas an incident to available lost motion operation of the piston relative to the shift rail in Syrovy et al., and the piston rod relative to the lever operating member in Neracher et al.. l

customarily there is also provided an ignition interrupter switch operated by movement ofthe piston in Syrovy et al., or by the 'piston rod in Neracher et al. Moreover, as in the above patents, there is provided an electrical system intended to accommodate interruption of the engineuignition only during the disengaging stroke of the piston, it being so arranged that even though the ignition interruptionV switch closes on the return `(engaging) stroke, the ignition is notordinarily grounded out because at `such time neither `of the parallel arranged kickdown and governor switches which are `arranged in series with the ignition interrupter switch and in series with the valve solenoid ina parallel circuitingis closed. Hence ring of the engine is not usually interrupted during `acceleration from Yvehicle standstill in the slower speed ratio drive.

As improvements upon the Neracher et al. system of control,y it has also been suggested, as shown in the patents to Albert E. Kimberly, Jr., 2,427,408, granted September 16, 1947, and Victor E. Matulaiti's 2,291,189, granted July 28, 1942, to' arrange the governor and kickdown switches in series with a ground and the valve solenoid and to provide a separate circuit for the i'gni'- tion interruption control that includes the interrupter switch and means Vsuch as an additional switch or mechanical control means in'- tended to render the ignition interrupter switch although actuated, operative to interrupt the ignition in only one direction of movement of the fcoilacts as a parallel impedance piston rod, whereas in Neracher et al. and Syrovy et al. aforesaid, the ignition interrupter switch is arranged in series with parallel governor and kickdown circuits.

Although the foregoing described arrangements have in general been satisfactory, they have been open to one or more unforeseen conditions of operation which it is desirable to avoid in order to provide a foolproof system. Thus in certain of the prior systems it has been possible to obtain ignition interruption while the transmission was in its lower gear, i. e., when the shiftable drive control element is disengaged, but at a time when the vehicle sneed was such as to reduire the governor to call for an upshift. Under these conditions the shiftable drive control element moves against its blocker but obviously cannot engage until the relative speeds of the engageable drive control elements are synchronized by deceleration of the engine through accelerator releasing movement. Hence, should the operator instead of releasing the aclcelerator, accidentally or deliberately depress the accelerator to wide open throttle position in demanding further acceleration from the transmission (thus closing the kickdown switch) ignition interruption could occur because the kick- `down operation would also vent the servomotor to allow the piston to recede and operate the ignition interrupter switch and even though the shiftable driven control element was not engaged.

This condition has also been found to occur under similar conditions when closing, opening and re-closing of the kickdown switch occurs due to unsteady pedal pressure or because of relative motion between the engine and throttle linkage.

Furthermore, in the arrangement disclosed by Neracher et al. and Syrovy et al., especially where a higher resistor type of ignition harness has been employed, some lurching of the vehicle has been noticeable in vehicle operation during upshifts. It is believed that in a circuiting wherein actuation of the interrupter switch places the ignition primary coil and the solenoid of the control valve in parallel circuits, the solenoid of low value to the primary coil of the ignition and causes the spark delivered by the secondary at the plugs at the time of current flow thereto to be weakened. In this connection, it .may be observed that under normal engine operation the higher the engine R. P. M., the lower is the secondary voltage, and since the upshift takes place at a substantial R. P. M. the effect of the low impedance is to weaken the spark suiiiciently so that it may be unable to keep the engine running momentarily, as by causing the engine to misfire. This condition can occur, for example, in the Neracher et al. arrangement and in the Syrovy et al. system when the relay coil of the latter has a low impedance eirect on the ignition primary.

An object of my invention is to provide an improved ignition interruption control adapted for use, for example, with a transmission control system of the types disclosed in the aforesaid patents and which is capable of operation without accommodating actual ignition interruption or misring of the engine during the return i. e., upshifts stroke of the piston, and which will positively, so far as now known, limit ignition inter- `ruption to only such occasions when it is intended to facilitate relative disengagement o; the drive control elements.

Another object is to provide a transmission shift control system having means for interrupting the engine ignition when eecting disengagement of interengaged drive control elements but which system incorporates means associated with the motion transmitting means for the disengageable drive control element for preventing ignition interruption when the drive control elements are not engaged.

It is also an object of the invention to provide a transmission drive control system having means for interrupting the engine ignition when effecting a downshift and which includes means for preventing said interruption of the engine tion in a vehicle speed range in which an uplshift operation has been previously initiated, but

not completed to the point of eiecting engagement of the drive control elements.

Still another object of the invention is to provide a transmission shift control system having means for interrupting the engine ignition when effecting a downshift, but which system inhibits weakening of the ignition spark intensity during the upshifting operations.

Still another object is to provide a transmission shift control system having means for interrupting the engine ignition when effecting disengagement of the drive control elements, but which system provides safeguards both against weakening of the ignition spark intensity during upshifting and against ignition interruption when a driver downshift operation'is initiated in a vehicle speed range accommodating an upshift but which upshift has not been completed.

A specific object of the invention is to provide a transmission shift control system having means including an ignition interrupting switch for interrupting the engine ignition when eiiecting disengagement of interengaged drive control elements one of which elements is a shiftable element, which interruption means includes control means associated with the motion transmitting means for the shiftable element and with the interrupter switch for preventing actuation of the ignition interrupter switch during engage- 'ing operations of the shiftaole element and during a kickdown operation initiated when the shiftable element is not engaged but is against its blocker.

Another specic object is to provide a transmission shift control system having switch means for interrupting the engine ignition and which includes controllable structure operable upon said switch only when eifecting disengagement of the interengaged drive control elements.

Other objects and features of my invention will be apparent from the following description wherein:

Figure l is a diagrammatic plan View of the driving power plant for the vehicle;

Figure 2 is an elevational View partly in section of my invention as applied to a semi-automatic four speed forward and reverse transmission, a part of the control system being schematically illustrated, the manually operable clutch sleeve being shown in its forward or high range position for starting the vehicle from rest, and the power shiftable mechanism and power operable clutch sleeve being shown in the released position of the latter;

Figure 3 is an elevational view similar to a por- .shiftable clutch :.sleeveintits direct drive or engaged gpo'sition and vthe power shifting mechamsm iin :the :corresponding iposition; Y

'.:Figure 114 is .a viewrsirnilar to that-oi Figures/.9. vand 113 illustrating the pistonof the power vshift mechanism in its position-about to initiate `disl,engaging movement of the Vpower shift sleeve;

and

:Figure 75 isa-'sectional elevation taken at 5-5 of .Figure .-2.

In the drawings in which similar numerals sindicate similar ,parts of the structure, Figure vl 'illustrates a typical motor vehicle power plant uhaving Iaconventional Iengine A .for transmitting pow-.er through fa propellershaft I0 to drive the :rear 4ground :wheels '.I-I. *In lthe housing IB there .may fbe tprovided :a vfluid power transmitting decvice, .such fas n huid .coupling :arranged I'in ltandem with a1masterfrictionclutch of known type, the rlatter being releasable to aun'couple the engine `from the transmission lby operation of a conven- .tional clutch pedal ris. Rearwardly 'of the housing;B:is a transmission-Cwhichrmay be any type Aincorporating positively engageable drive control felements 'of a character usually subject to substantial thrust or torque load in operation, the `latter conditionsmaking the Ause of some formoi 'unloading means desirable torinsure release ofthe vdrive control elements when speed change re- -quiring `disengagement 'of 'these elements is necessary.

The transmission C may be 'of various known types. LFor purposes 'of illustration I have shown =iI1Fgure'2, a commercial'form `of four-'speed and .reverse V'countershaft underdrive transmission. t

Thistransmission comprises an input or driving shaft I3 vwhich receives drive from the engine VA ibywayo'f the clutch assembly B, and an output or driven shaft :I d'which is adapted tetransmit'drive .to the propeller shaft Ii. The driving `shait i3 carries the main driving .gear or pinion I5 and a set fof positive jaw clutch teeth :I6 which are :adapted to be engaged `by the ,teeth of a jaw clutchsleeve D. As will be hereinafter seen, the 'sleeve D together with the clutch teeth ri coinlprise relatively mov 'ble drive control elements y'for leilec'ting stepup and stepdown manipulation .of the transmission.

kThe clutch sleeve vD is slidably splined on'teeth, not shown, of a forward hub portion. of the high lor third .speed gear 22 which is rotatably journalled. :on 4the driven shaft lll and Vadapted `to be clutched thereto through a jaw clutch sleeve F slidably splined on :a hub, not shown, driving'ly .carried bythe :shaft I4 andinterengageable with jaw .clutch teeth .26 carried by the gear 22. The forward shift of 'sleeve D for clutching with teeth I6 'is'normally controlled Yor .impeded by a toothed blocker E whereby clutching is limited to 4synchronous relationship in the speeds of rotation of gears I5 and 22 and, in the particular construction illustrated, limited to engine coast conditions obtainable by accelerator releasing Amovement to secure deceleration of the engine. `The blocker E is4 journalled on a conical surface, not shown,carried by the shaft I3 against which itis frictionally urged by a'spring, also not shown, and has `a 'limited Ylost motion connection with the sleeve D or gear 122 whereby it may rotate to place .its teethin blocking .relation to the teeth of sleeve l D whenever `the gear I`5 rotatably leads or lags the sleeve D. When sleeve D moves .past the blocker E into "engagement with the -clutch'teeth It, the gears -1Il5andf22 are `.placed in la two-way .direct drive relationship.

- lpart of the input shaft I3. Also loosely lcountershaft gears.

obtaining reverse "G, gears `3:3 and '21 Gear `22, .as stated above, .is loosely journalled on the driven shaft .I4 whereas ythe pinion VI5 journalled on the output shaft I4! is a low or first speed gear 2 having jaw clutch teeth 28 engageable by the sleeve F. Associated with the sleeve F on each side thereof Vis any commercial type of blocker synchronizers 29 such that clutch F may be shifted from a 'neutral position disengaged from teeth 25 and 28 fo wardly to a high range position to synchronously clutch shaft I4 with 'the high speed gear 22 through the teeth 26 or rearwardly to Aa vlow range position to synchronously clutch .shaft Hi with the low speed Ygear 21 at its teeth 28. Manual shifts of the sleeve VF are facilitated by release of .the main clutch at .B by means of the clutch pedal I2.

l.Gear 22 isalso adaptedto be drivenromgear i5 ata speed different from 1*:'1 and vto this end I Ahave shown a countershaft type one-way 're- `duction driving means between'these gears. `This drive comprises the coaxially rotatable countershait gear 'si and cluster gear 3l wheels y32. '33 respectively, in constant mesh with gears I5, 22, and 2l and an overrunning roller lclutch G operably interposed therein between the gear 35 and cluster 3i. A stationarily mounted countershaft 34 provides a journal support for the Assuming the usual clock'- wise rotation of shaft I3 as Viewed when looking from front to rear of Figure 2, lthen overrunning clutch G will automatically clutch gear 3D and cluster 3i together lwhen gear 36 is driven counterclockwise at a speed tending to exceed that of the cluster 3| and automatically release the drive 'between these gears to allow gear 30 to slow down below the speed of cluster .3L For drive an idler gear (not shown) having constant mesh with the gear '33 is shiftable rearwardly into mesh with a gear i5 xed on shaft I4, the clutch F .being then in its neutral position disengaged from teeth 25 and 23.

As thus far described, it will be apparent that with the parts arranged as in Figure 2, sleeve F being then in high range position engaged with teeth 25, drive off shaft I3 will cause the output shaft Id to be driven at a reduction drive (third speed) through the gears I5, 3E! overrunning clutch G, gears 32, 22 and sleeve F. Should the sleeve D be biased forwardly during this reduction drive, blocker E will obstruct sleeve D in an intermediate position of its shift preventing ratcheting of its teeth with the teeth i6. However, if the driver releases the engine throttle control in `the form of the usual accelerator pedal then, as will be apparent, overrunning clutch G will allow gear 'I5 and teeth I 5 to slow down relative to the sustained speed of gear 22 and when the speed of gear I5 reaches synchronism with that of gear 'blocker E will move to an unblocking position yand allow sleeve D to move further forwardly to clutch its teeth with teeth I6 to the position 'shown in Figure 3, to provide the direct drive (fourth speed), clutch G continuing its overrunning operation. Upon return of sleeve D to disengaged position shown in Figure 2, followed by speeding up the engine, overrunning clutch G will automatically engage to restore the reduction drive.

When clutch sleeve F is shifted rearwardly to low range position to clutch gear 21 to shaft Ill an overrunning slow speed drive (first speed) is transmitted from the shaft i3 to the shaft Ill by way vof the gears t5, 3B, overrunning clutch and `sleeve F.` At .such time as the sleeve D is biased forwardly and the shaft I3 is kallowed to slow down to permit the teeth I6 to become synchronized with the sleeve D, the sleeve will move past the blocker E and clutch with the teeth l to establish a two-way relatively fast speed drive (second speed) in the low range, which drive will be from the shaft I3 through the sleeve D, gears 22 and 32, gears 33 and 21, and clutch F to the shaft Ill, the clutch G overrunning by reason of the cluster 3| rotating at a higher speed forwardly than the gear 38.

It will be understood the driver may start the vehicle from rest in the low range drive and subsequently shift to the high range incident to momentary release of the master clutch and this either prior to or subsequent to engagement of the clutch D. Most drivers, however, usually start the vehicle from rest in the slow speed ratio of the high range and at a subsequent higher speed obtain the automatic upshift to direct drive by momentary release of the accelerator pedal described above.

A more complete description of the transmission specifically illustrated in this application and its method of operation is set forth in the patent to A. J. Syrovy et al. 2,490,604, aforesaid.

A speed responsive governor means O is provided to control forward bias of the sleeve D as well as rearward bias thereof as will be presently more apparent. Moreover, during drive in either second or fourth speeds referred to above, a downshift to rst or third speeds respectively may be effected by way of overruling the governor O through driver depression of the accelerator pedal M to substantially wide open throttle position, which operation is referred to in greater detail below.

As seen in Figure 2, I have illustrated a servomotor H by which to obtain power actuation of the clutch sleeve D, the motor here illustrated being of the pressure differential and spring operated type and in the disclosed embodiment functioning by means of fluid pressure. This motor preferably comprises a cylinder 3S slidably receiving a piston 31. The piston slidably receives a shift rail or rod 33 mounted to operate in the guideways 39 and 128. Fixed to rod 38 is a yoke 4i, a hub'portion 42 of which is secured to the rod 38 by means of a dowel screw 43. The rod 38 and yoke 4| constitute motion transmitting means S for the sleeve D, the yoke 4| as seen in Figure 2, having lingers 44 engage ing in a groove 45 of the sleeve D to effect shift thereof.

A relatively small preloaded engaging spring 45 surrounds the rod 38 and is disposed between the hub of piston 31 and the hub 42 of the yoke 4|. This spring 48 provides a lost motion thrust transmitting connection between the piston 31 and the hub 42 of the motion transmitting means S such that the piston 31 may be moved forwardly (to the left in Figure 2) for its power stroke, the piston 31 continuing its forward motion by fluid pressure even after the clutch D has been moved against the blocker E until the lip 1 of the piston uncovers the relief port i8 of the cylinder 36 whereupon forward movement of the piston 31 will cease, the fluid pressure being then expended through the relief port 48.

During the said forward movement of the piston 31 the engaging spring 43 is compressed and urges the rail 38 through the hub 42 of the yoke 4| forwardly thus in turn shifting the clutch sleeve D to its intermediate position blocked by .the blocker E;` Subsequently upon synchronous rotation of the teeth tained in response to I6 and sleeve D beingobaccelerator releasing movement, the sleeve D is moved through the blocker E into engagement with the teeth |6 of the drive pinion l5, which is its fully engaged upshifted position shown in Figure 3, establishing the previously described direct drive between the shaft |3 and gear 22.

A relatively large down spring 49 is disposed between an abutment ring 50, located at the forward end of the cylinder 33, and the piston 31. This spring serves to return the piston 31 and sleeve D from their Figure 3 positions to their downshifted or disengaged position shown in Figure 2. It will be lobserved from Figure 3 that the piston 31 when in its furthest forward position shown in this gure uncovering the port 48 has moved further than the shift rail 38 such that a gap 5| is created between the piston 31 and a shoulder 52 of the portion 53 of the shift rail. This gap 5| facilitates a lost motion movement of the piston 31 relative to the shift rail 38 prior to disengaging movement of the sleeve vD which can only commence following abutment of the piston 31 with the shoulder 52. As previously noted, forward movement of the piston 31 is stopped upon uncovering the port 48, the latter permitting any excess pressure required to hold the piston 31 in its furthest position to be relieved and preventing the building up of such excess pressure in the cylinder.

The pressure fluid supply system is shown in Figure 2 and comprises a suitable supply source 50, which is usually the transmission sump. A pump Q of the rotary gear type is mounted on the shaft I4 and has its rotor 6| driven by that shaft, oil being drawn from the supply source 30 through the conduit 82 to the pump inlet 63 and is delivered under pressure at the pump outlet |54 to the conduit 65 and then to the passage 88 under control of a ball valve K. A relief valve, generally designated by the numeral 61 and provided at the pressure side of the pump between the outlet 64 and the ball valve K serves as a relief valve in the event the valve K is not open in normal operation of the transmission to thereby permit pressure uid trapped behind the piston 31 to be dumped back into the' transmission sump Si! through the conduit 81a.

When the valve K is closed, oil under pressure is forced directly from the pump through the passage 66 to the cylinder 36 where it moves the piston 31 forwardly to effect forward movement lof the shift rail 38 in the manner described above whereby the shift sleeve D is operated from its disengaged position in Figure 2 to its engaged position of Figure 3 to establish second or fourth speed ratio drive depending upon whether the clutch F is engaged with the first speed gear 21 or with lthe thirdV speed gear 22.

Valve K is closed by bias of a valve spring 6B acting against a ball 69 to close a discharge port 1B opening into a p-assage 1| draining to the sump or supply source 68. The valve K is actuated to its open position under control of an electromagnetic device comprising a solenoid L having a plunger 12 connected with the movable core of the solenoid. The valve K is closed when the solenoid L is deenergized. The spring 68 then actuates the ball 69 against a seat 13 to close the port 10 and effects movement of the solenoid plunger 12 to its retracted position. The valve K is open when the solenoid L is energized, the solenoid core then moving the plunger 12 downpreloaded downshift or kickg1 wardl'yv to push the'ball Eil-off the-seat` 13 of port` 102 The oil may now ow fromv the' pumpQ throughthe conduit 65'; port 10, passage 1|', back tothe sump 60.

When'the valve K is-open, it isimpossiblefor sufcient uid pressure to develop in the passage 66 to moverthe piston 31 againstthe force exerted by the' piston return spring i9 whichA then? maintains thev piston at they extreme rearward position of its capable movement; Hencel the piston..31 isi actuated by huid pressure-l only" establish secondI and fourth speedsd respectively at which time the valve K` is' closedv and the solenoidL deene'rgized.- Figure 2 shows'the'valve K inrits.y open position andthe piston' 31' in; its position retracted bly' spring' de, l and Figurer 3' shows the valveKin itsclosediposition andthe piston` 3111 in'- itsV furthestA forward position under' control ofthe pressure fluidJ Energization and'deenergization ofstheisoleno'id L-is brought about by. operationlfrom one'position tozanoth'er of either of two control members, one actuated in response t'o vehicle speed; andthe other in response to manipulation by. a driver' control member. One of these control members is the governor O, and the otheris akiclrdown, switch generally designated. by the letter P; Suit able electrical circuit m'eans are provided fory effectuatingthe control operation of' the-governor and kickdown switch over a suitablesource' of electrical energy, for example, a storage battery `has one sidey grounded as at 16 by a conductor 11 andtsother' side con-V nected by. a rconductor 18-5 through" an ammeter 19`to theignitionswitch 8i): A conductor 8| connects. theignition switch .with one terminal. 82 of the solenoid L, the other terminal 83 of the solenoid being-connected by-avconductor 841 with av terminal of a switch generally designated by. the letter N which is operated bythe governor O and which has a'second aground 88 by avconductor 89: From'thegovernor switchterminal a conductor et extends to avterminallg'lof the kiok'down snap switch P-,.

this switch 'having asecond terminal 92 connected to aground 93 by a conductor 94'.V

Theu governor switch `N closed by'r a. movablev conductor. switchbar 95 operated by an insulated sliding sleeveA 'eofthe governor O, theswitch beingclosed when the bar ebridges the ter-v minals 851'and 811 The kickdownswitch Pis of the snaptype and .has a conductorfbarwhich bridging the. terminals 9 I fand" closesthe same by 9`2I of kthis switch.

Thus by means of"thegovernor.switch Nand'v the' ki'clc'down .switch P, two parallel ground'circuits areprovid'ed for the solenoid L, the governor switchiN' opening at a speed proportional to vehiclerspe'ed" established by the' drive connection' IMI, IUI between thegovernor O and the counter-'- shaft' cluster 3|. It'will be 'understood that the governor driving means" I BI may if' desired bei on thefdri'ven 'shaft 4.'

is 'inopen 'position undencontrolof' a coil spring thef-throttle valve-operating' linkage isa' 'lever' |105' pivotallysupported at IDE* andfhaving.v spaced fingers-or projections |08;- IIIl-for4 operating the actuating finger# I I 2 v'of/fthe snap the solenoid L. Thusy v terminal S1 connected to- A Kswitch? The mechanism is *preferably arranged'suchj thaty in operation, the `switch nge'r I-I 211sl engaged by the' lever projection I8` as the'throttle valve` in re?- sponse to depression of the accelerator' M- approaches its full open` throttle position;sotha't` the-switch Pis closed withfsnap.actionduringape proximately. the last 5 or so of throttleopening"-v movementp It willb'e understoodthat' the'cpera' tion of thisswitch may be adjusted'to occur` sub'- se'quent to full open throttle position by thepr'o; vision of suitable lost motion mechanism suchfas disclosed in the patent-to Neracher et al. 2;455,943. When the accelerator M is released, the finger IIIII comes into contact with" the yactuating finger II2Y of the switch near the fully released-'position of the accelerator to actuate the switch P toits open' position,v again by'snap action, the parts being-so arranged that the' switch P will be opened` byY nger it i) whenever the :accelerator pedal is-fully released; Y

The ignition mechanism` generally designated' by the letter J isvof' conventional type and includes an ignition coil |2Ela distributor |22g-anda breaker |24. From the primary coil |26fan ignition grounding circuit is providedl that eX- tends through the conductors |21,v |28-,r |759y to` terminal I t@ of anormally open interrupter switch T and thence from terminal;` IIBIr thereofby the conductor |32 to the ground te providedby theA governor switch N o rby conductors I 32 and-- tov the ground 53- of thevkick'down IswitchP.'y y

As noted. above, prior control'- circuits andstructuresmade feasible-interruption oftheignition during anuncornpleted upshift through accidental or deiiberateroperation'of the lnckdc'wn` switch by the accelerator and in systems providing a common ground for the ignition primary coil and the solenoidAL inparallelarranged circuits made it possiblek for the solenoidllV toV act as a parallel impedance of low value to theV pri'- mary coil and weakenl the spark delivered by the secondary of the plugs IS when current V'vvthereto took place. A feature ofthe present invention is to overcome these difficulties.-` In order to accomplish this lpreferably'provide a finger orrmember I''iladapted to actuate the operating plunger |35 of the interrupter switch T during the rearward or clutch D disengaging.. movement of the piston 31 and rail`38 only. The finger Iis preferably pivotally mountedon a' shouldered portion I|112 at the rearwardendof" an overhanging axially movable supportrodf or" bar IM journalled at |46 in thetransrnission casing. and having its vforward end'portion Ill' preferably formed of half-moon sectionV and loosely fitted into an opening ofv similar shape inthepi'sl ton 31so as to render ther'od IM' non-rotatable" and p'rovidea bearingsh'ould'er betweenthe' rod" |44' and piston' 31. A' compression spring' |52XJ having one end' seated' on the" transmission 'casi ing and' the other end bearing'against a side' face" of the finger Ill@ provides" a constant'bias cause ing the finger |40 `to bemaintained'ag'ainst'its shoulder |62 andtherod IM against the'piston 31 so that'th'e' rod" Ilfollow's 'allrnovenient of the piston 31'.`

The finger' I e@ vis preferably; asseen in Figure" 5', of' flat elongated character and' providedwith" opposite wings or arms |53l and' |512 respectively; Offset from the wing |521" is a radial'proj'ection' |56` forming a'reentrant angleornotch |51 with` the wing |54. The function of the' projectionvr |56l is to actuate the plunger If'of interrupter switch T under conditions'hereinafterv morefully'l set forth. Surrounding the rod'l44 Lis a'tors'io'rf rod |44 and its opposite end arranged to bias the finger |40 in a clockwise direction looking in Figure 5. The rod |44 has sufficient length to enable the finger |40 to be positioned rearwardly of the switch T in the disengaged position of the clutch D, as seen in Figure 2, and such that the wing I 53, as seen in Figure 5, overlaps the rearward end of portion 53 of the shift rail, the opposite wing |54 being maintained by the spring |58 against a flat guide surface |55 preferably formed on the transmission casing coextensive with the rod |44. The rearward end of portion 53 of the rail 33 is provided with a cam shoulder |62 for actuating the finger |40 to a more horizontal position upon forward movement of rod |44 and finger |40 relative to rail portion 53 as an incident to the lost motion operation between piston 31 and rail 38 that occurs during the upshift operation after the sleeve D is against the blocker E. In the engaged position of sleeve D the nger |40 is forwardly of the switch T andin the position shown in Figure 3 and in phantom in Figure 5.

' The operation of the transmission and control system will now be described. Let it be assumed that the vehicle is at a standstill with the manual sleeve F shifted forwardly in engagement with the teeth 23 of the third speed gear 22, as seen in Figure 2. At this time the governor switch N will be closed and provides a circuit from battery 15 to ground 83 by way of the conductors 8| and 84 and solenoid L thus energizing the latter whereby the solenoid rod 12 maintains the ball 69 of the valve K in its down position venting the motor H so that spring 43 holds the clutch sleeve D in the position shown in this figure. The interrupter switch T is open as shown, the outer end |36 of the operating plunger of the switch T being free of the projection |56 of the actuating finger |45. is open since the accelerator pedal is released.

By depressing the accelerator pedal the vehicle is driven in third speed ratio drive. At some predetermined speed of vehicle travel, for example, 12 to 14. M. VP. H. (6 to '1 M. P. H. in rst speed), the governor O actuates the switch N to open position. The solenoid L is thereupon deenergized and valve K closed by operation of the spring 68 which moves the ball 69 to close the port 10 at the entrance of return passage 1|, thus permitting pressure to be built up by the pump Q in the passage 66.

At the moment of operation of the solenoid L the ignition switch operating nger |46 is, as described above for the disengaged position of sleeve D, in the position shown in Figures 2 and with the wing |53 of the finger overlapping the rearward end portion of the shift rail 38 and with the wing |54 urged against the guide face |56 by the torsion spring |58.

When the uid pressure builds up sufhciently, the piston 31 moves forwardly for its upshift stroke and comes to rest at the position shown in Figure 3 where the relief port 48 is uncovered to relieve the fluid pressure and maintain the piston at this position. The forward movement of the piston 31 is utilized in compressing the springs 4G and 49. Initially the spring 46 moves rail 38 and thereby the sleeve D to its blocked position against the blocker E. Simultaneously, the spring |52 causes the rod |44 and finger |46 to follow the piston movement. During this movement the finger |40 is in the full line position thereof shown in Figure 5 such that the pro- The kickdown switch P' jection |56 thereof moves in a path in line with the operating plunger |36 of the switch T which I will denominate the primary path of movement of the linger |49. Moreover, at the end of this initial movement the portion 53 of the rail 38 is then still under the switch plunger |36. Then lost motion movement takes place between the piston 31 and the shift rail 38 during which the springs 45 and 49 continue to compress and the rod |44 carrying the switch actuating finger |40 is urged forwardly by the spring 52 to follow the movement of the piston 3,1. During the initial relative movement between piston 31 and rail 38 the linger |40 is rotated counterclockwise by the cam portion |62 of the shift rail 38 from its primary path position wherein the projection |56 is in line with the plunger |36 of the switch T to the position shownin phantom in Figure 5, wherein it may move in a bypassing or secondary path relative to the switch plunger |36` During the remainder of the relative movement between piston 31 and rail 38 the finger |40 rides upon the enlarged end of the shift rail 38 moving forwardly past the switch T to the position shown in Figure 3. Thereafter upon accelerator release to synchronize the speeds of the sleeve D and the clutch teeth I6, the sleeve D is moved by spring 46 acting upon the rail 38, to its engaged position seen in Figure 3. During this engaging movement the rail moves forwardly relative to piston 31 and nger |40 but the latter remains in its Figure 3 raised position Where it is retained by the rail 38.

Since switch T is not operatedduring the forward movement of the piston the ground circuit for the primary coil is not closed and hence the ignition is not interrupted. Moreover, as the switch T is in series with the ground 88 of governor switch N and also with the ground 93 of kickdown switch P, should the accelerator pedal be depressed to full open throttle position to actuate the switch P and energize solenoid L at a time when the governor switch N is open and the sleeve D is against the blocker, the ignition will not be interrupted unless the switch T is closed. However, in the situation described the switch T will not be operated by the nger |40 when the pressure is released in the cylinder 36, because at that time the shift rail is in the blocked position of sleeve D and its end portion 53 is, as described above, below the switch T plunger |35 and holds the ngerr|40 in its raised position of Figure 3. Therefore, the rearward movement of the piston 31 merely causes the projection |56 of the finger |40'to move in its secondary path past the switchand nally to move with the rail to the position shown Vin Figure 2 iwhereat the finger |40 drops to its initial posiion.

It is to be noted that in the described situation the interrupter switch T is neither operated during the forward or return movement of the piston 31. Moreover, the ignition cannot be weakened during upshift since the switch T cannot be closed.

Once established in fourth speed, a downshift to third speed is effected either by manually closing the knickdown switch P by means of the accelerator pedal M or by the automatic closing of the governor switch N when the speed of the vehicle drops below the upshift speed set for the transmission. For example, when the driver desires to manually effect the downshift from fourth speed he fully depresses the accelerator M. During this operation the switch P is closed. V

Since the engine is then deliveringits full power, itis desirable to effect torque, relief at theteetli [Si to facilitate the release of sleeve D for the downshift. At this timethe switch T operating mechanismis in the position shown in Figure 3, with the piston 31 adjacentthe relief opening 48, the shi-ft rail 38vin its fully engaged position forwardly, and the interrupter switch finger lMlin its horizontal position held bythe portion 53 of ther shiftrail. Closing of switchP applies ground 9.3V to the solenoid Ly circuit from the battery l causing encrgizaton ofthe solenoid and opening of the valve K to vent the motor H.

As no tedabove, the interruptor switch I which connects by the conductors |28 and |29. with the primary |26 of the ignition coil,is in series with therground 93 established by the kickdown switch P. Hencewhen pressurel isvented in the cylinder 35 the' sleeve D usually initiallyv remains rengaged by. reason ofthe torque on its teeth and the piston 3,1 beginsits return movementunder urging ofthe spring 4S. Just before the piston 3,1 engages, as seen in Figure 4, the shoulder 521 of the.a shift rail, the finger |40 will move past the rearward end of the shift rail and allow the torsionspring |593 to rotate the fingerl Mi! clockwise to the1r primary path position shown in full lines in Figure 5 thereby placing the projection los o f thenger in line with the operating plunger |36l of the interrupter switch T. Manifestly,l a snapv action will be produced in this shift of the switch operating finger and while the piston 3l continues its return movement. Immediately thereafter and again prior to the intersection of the piston with the shoulder 52, the projection |.56offthe nger |40 will move in the primary path, abut the plunger |36A of the switch, and camitupwardly, the switch bar thereupon bridging the switch terminals |3|, |32 to close this switch and ground the primary of the ignitionthrough the ground 93 of kickdown switch P. The engine now missing fire, unloads the torque on the teeth of the member ls and the teeth o f the sleeveD and permits disengagement of the sleeve D, whereupon the piston 31 completes its rearward or return stroke back to the position illustrated in Figure 2 together with the shift rail during which ,movement the switch operating' nger |40 remains in its primary path positionshown in Figure 5 Iin overlapping relation relativeto the rail 38. It will be understood thatk the ignition, is restored to normal operation assoonas the fingerV |40 moves to the rearward side of theswitchT to permit the plunger |35;l to restore the switch to open position. When the accelerator M is later released sufficiently to open switch P, fourthspeed may be again restored as previously described, provided the vehicle speed isstill such that the governor switch N is open.

For the automatic downshift from fourth to third under governor control of the vehicle governor O, it is only necessary to reduce the vehicle speed to or below the speed atwhich the governor switch N normally closes. This closing of the switch N energizes the solenoid L by effecting a circuit from `the battery to the ground 88. The motor I-Iy is then vented as described above with respect to the kickdown operation and the interrupter switch T is similarly operated.

When the sleeveA F is in its rearward orvlow range position, then upshift` and downshift movement of sleeve D will be the same as that set forth for operation ofV this sleeve in the high range setting. However, since; the governor O is drivenzrcnt-.thei-countershaftias atd -l ,.in; Figure.;

2, the. governor O will function at asomewhat lower car speed dependingon the gear ratios for first. and second as compared with third and fourth as will be readily'understood.

From the foregoing description of my invention, it will be apparent that I have provided a.

novel and foolproof ignition interrupter control system and structure for transmissions having both governor and manually controlled downshiftingv wherein ignition interruption for dis.- engaging engaged clutch elements is initiated at required times only.

' It will also be apparent that the invention is applicable to other forms of transmissions.`

Moreover, `although the disclosed embodiment of the invention is well adapted for carrying' out the objects hereinabove set forth. it will be understood that various modifications, changes, and.

substitutions coming within the spirit of my invention and within the scope of the appended claimsY are also contemplated.

What is claimed is:

l. In a power transmission for driving a` vehicle having an engine provided system; a shiftable transmission drive control-element shiftable from a first position disengaged relative to another drive control element tov a second position of engagement with said other; element and shiftable out of said second posi-v tion when operation of said ignition systemv isl momentarily interrupted to relieve the thrust load at said shiftable element, motion transmitting means for shifting said shiftable drive control element, actuating means operable upon said motion transmitting means for effecting shift of said shiftable drive control element between its two said positions and accommodating lost motion operation of said actuating means relative to-said motion transmitting means during operation of said actuating means to effect shift of said shiftable control element between said positions, circuit means including a switch device for controlling ,the ignition system, and mechanical means associated with said actuating means operable upon said switch device during said lost motion operation of said actuating means when effecting shift of said shiftable control element out of said second posi-tion and means on said motion transmitting means operable upon said mechanical means as an incident rto lost motion operation of said actuating means when effecting shift of said shiftable element from said rst to said second position forpreventing operation of said mechanical means upon said switch device during shift of said shiftable member from said rst `to said second position.

2. In a power transmission for driving a, vehicle having an engine provided with an ignition system; a shiftable transmission drive control element shiftable from a rs-t position disengaged .L duringgopera-tionof saidtuatingmeansto effect with an ignition` shift of said shiftable control element between said positions, circuit means including a switch for controlling the ignition system and mechanical means including a portion movable along a pair of paths in one of which only it is adapted to actuate said switch, said mechanical means being associated with said motion transmitting structure and actuating means aforesaid and operable to and along said one path during said lost motion movement of said actua-ting means incident to effecting shift of said shiftable control element out of said second position for operating said switch to momentarily interrupt said ignition and operable into and along the other of said pair of paths during said lost motion movement of said actuating means incident to effecting shift of said shiftable element from said nrst position to said second position.

3. In a power transmission for driving a vehicle having an engine provided with an ignition system; a shiftable transmission drive controlling element shiftable from a first position disengaged relative to another drive control element to a second position of engagement with said other element and shiftable out of said second position when operation of said ignition system is momentarily interrupted to relieve the thrust load at said shiftable element, motion transmitting means for shifting said shiftable element, actuating means including spring means operable upon said motion transmitting means for eecting shift of said shiftable control element between its two said positions, circuit means including a switch for controlling the ignition system, a switch actuating member movable with said actuating means and having a portion selectively positionable for said movement in two paths along one of which it may effect opera-tion of said switch but not along the other, and means associated with said motion transmitting means operable for directing said member into said other path during operation of said actuating means to eiect shift of said shiftable control element from said first to said second position and accommodating positioning of said actuating member into said one path during operati-on of said actuating means to effect shift of said shiftable element out of said second position.

4. In a power transmission for driving a vehicle having an engine provided with an ignition sysm; a shiftable transmission drive con-trol element shiftable from a first position disengaged relative to another drive control element to a second position of engagement with said other element and shiftable out of said second position when operation of said ignition system is momentarily interrupted to relieve the thrust load at said shiftable element, motion transmitting means for shifting said shiftable element, actuating means including spring means operable upon said motion transmitting means for effecting shift of said shiftable control element between its two said posi-tions, said motion transmitting means and acuating means being arranged and constructed to provide for lost motion therebetween during operation of said actuating means for effecting shift of said shiftable control element from its i'lrst to its second position and from its second to its rst position, circuit means including a switch for controlling said ignition system, a pivotally mounted switch operating member movable with said actuating means and selectively swingable into position for movement in two paths along one of which it may operate said switch but along the other of which it may not operate said switch, and means associated with said motion transmitting means engageable with said switch operating member for directing said member into said other` path during said lost motion movement occurring when eiecting shift of said shiftable control element from its first to its second position, said motion transmit-ting means accommodating movement of said member from said other path into said one path during said lost motion operation occurring when effecting shift of said shiftable control element from said second position to its said first position and said member being adapted to operate said switch during said last-named lost motion movement.

5. In a power transmission for driving a vehicle having an engine provided with an ignition system; a shiftable transmission drive control element shiftable from a first position disengaged relative to another drive control element to a. second position of engagement with said other element and shiftable out of said second position when operation of said ignition system is momentarily interrupted to relieve the thrust load at said shiftable element, motion transmitting means for shifting said shiftable element, actuating means including spring means operable upon said motion transmitting means for effecting shift of said shiftable control element between its two said positionsjsaid motion transmitting means and actuating means being arranged and constructed to provide for lost motion therebetween during operation of said actuating means for effecting shift of said shiftable control element from its first to its second position and from its second to its first position, circuit means including a switch for controlling said ignition system, a pivotally mounted switch operating member movable Ywith said actuating means and selectively swingable into position for movement in two paths along one of which it may operate said switch but along the other of which it may not operate said switch, and cam means on said motion transmitting means engageable with said switch operating member,

for directing said member into said other path during said lost motion movement occurring when effecting shift of said shiftable control element from its rst to its second position, said motion transmitting means accommodating operation of said member from said other path to said one path during said lost motion operation occurring when effecting shift of said shiftable control element from said second position to its first position and said member being adapted to operate said switch during said last-named lost motion movement.

6. In a power transmission for driving a vehicle having an engine provided with an ignition system; a shiftable transmission drive control element shiftable from a rst position oi disengagement relative to another drive control element to a second position of engagement with said other element and shiftable out of said second position when operation of said ignition system is momentarily 'interrupted to relieve the thrust load at said shiftable element, a shift rail and yoke for shifting said shiftable element, means including a piston and Vspring means for operating said shift rail, and Vyoke to shift said shiftable element between ts two said positions, circuit means including a switch for controlling the ignition system, a switch operating member, support means for said switch operating member movable with said piston, said piston having lost motion movement relative to said rail and yoke during operation thereof for effecting shift of said shiftable control element between its first and its second position and between ts second and its first position, means for biasing said switch operating member into a path along which it may be moved to operate said switch, and means carried by said rail for actuating said switch operating member into a second path along which it may be moved without operating said switch, said switch operating member being engageable with its said actuating means during said lost motion operation of said piston occurring when effecting shift of said shiftable control element from its first to its second position for pos-itioning said engagement relative to another drive control element to a second position of engagement with said other element and shiftable out of said second position when operation of said ignition system is momentarily interrupted to relieve the thrust load at said shiftable element, means including a shift rail and yoke for shifting said shiftable element, a servomotor including a piston arranged for reciprocal movement, a first spring operable intermediate said piston and said yoke and operable to shift said shiftable element from its first to its second position incident to movement of said piston in one direction of its movement, a second spring operable upon said piston for effecting shift of said shiftable element from its second to its first position, means on said shift rail engageable by said piston in response to movement of said piston by said second spring, a switch op- @rating member, means movable with said piston for supporting said switch operating member and accommodating pivotal movement of said switch operating member between a first and a second path along the first of which said member is adapted tooperate said switch and along the second of which paths it may not operate said switch, said springs accommodating lost motion movement of said piston relative to said rail during shift of said shiftable element from its first position to its second position and accommodating lost motion movement of said piston relative to said rail incident to initiating shift of said shiftable element out of said second position, means on said shift rail engageable by said switch operating member during said first mentioned lost motion movement of said piston for actuating said switch operating member into its said second path for movement therein, means carried by said support means for biasing said switch operating member into said first path for movement therein during said second mentioned lost motion operation of said piston, and means for guiding said lswitch operating member during its said movement in said first path.

LOUIS B. FORMAN.

REFERENCES CTEii) The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,426,234 Neracher et al Aug. 26, 1947 2,444,953 Polomski July 13, 1948 2,448,678 McFarland Sept. 7, 1948 2,579,693 Orr Dec. 25, 1951 

